Pericapillary rosettes in the human spinal cord.

We have found large eosinophilic bodies in the pericapillary regions of the gray and white matter in the human spinal cord. These are entirely different from the previously reported pericapillary inclusion bodies (PIB). We have designated them pericapillary rosettes (PR), since they consist of clusters of round or ovoid structures of various sizes which form rosettes around the transversely sectioned capillaries. Positive staining with silver impregnation and anti-neurofilament antibody, the presence of the myelin around the bodies and the accumulation of neurofilaments within them indicate that axonal swelling is associated with the formation of PR. These bodies are not observed in individuals aged less than 30 years, and afterwards they increase in proportion to age. Over the age of 80, they are almost always found in the spinal cord, particularly in the gray matter of both the anterior and posterior horns at the thoracic and lumbar levels. Thus, the development of PR is closely related to the aging process.